Collision-induced dissociations of trimethylsilylated lysergic acid diethylamide (LSD) in ion trap multiple stage mass spectrometry

The first part of this work was devoted to the determination of the most sensitive GC-MS2 method for LSD detection on the ion trap apparatus. On neat samples, it has been shown that trimethylsilylation of LSD decreases the detection threshold by a factor 10 and that chemical ionization using acetonitrile as the reagent gas provides a method seven times more sensitive than electron ionization. The decomposition pathways of protonated trimethylsilylated LSD were determined owing to isotopic labeling and MSn experiments with n up to 4. The ion trap analyzer allowed the observation of intermediate ions that are not observed in triple quadrupole analysis. The resort to MS3 and MS4 experiments also permitted to show evidence of isobaric daughter ions and to attribute the corresponding structures.